Powertrain, generic (extended)

P2647 "A" Rocker Arm Actuator System Stuck On (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Here actuator A on bank 1 is believed to stay engaged: the rocker arms remain locked in the switched mode although the controller has asked for the default lift. GM's 2015 four-cylinder table 15OBDG05 detects this with the same intrusive lift toggle as P2646 but flags a filtered pressure-ripple value that falls below its limit; conditions are 1,200 to 1,800 rpm, 40 to 230 Nm, oil pressure 50 to 1,000 kPa, Type A after one trip. On the Honda-built 3.5 L V6 (L66) in GM's 2004 and 2005 tables, the VTEC pressure switch keeps signalling oil pressure for 5 s while the solenoid is off. On i-VTEC four-cylinders, Honda's bulletin 13-021 files a high-voltage switch reading under P2647 instead. Further causes: a solenoid leaking oil or a jammed locking pin. Expect rough idle, misfire or poor low-speed response.

Likely causes

Oil control solenoid leaks oil while switched off
Locking pin jammed in the engaged position
Faulty rocker arm oil pressure switch (Honda VTEC)

Symptoms

  • Rough or lumpy idle
  • Misfire at low load
  • Sluggish response when pulling away

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

rocker arm actuator a b1oil control valveoil pressure switch

Related codes

P2646P2645P2657P2652

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, en.wikipedia.org.